Department of Bacteriology and Immunology, The Harvard Medical School, Boston.
J Exp Med. 1937 Jul 31;66(2):207-27. doi: 10.1084/jem.66.2.207.
An analysis of some of the physiological factors active in Maitland tissue cultures has been presented in the hope that it may be of some value in clarifying the principles underlying tissue cultures in general. It has been found that the empirically determined necessity of using relatively small amounts of tissue in such cultures is dependent upon the fact that excessive tissue leads to a rapid change of reaction toward the acid side. Whereas tissue may remain viable in an environment as alkaline as pH 9 and over, viability is rapidly destroyed when the reaction approaches pH 6. Evidence is presented to indicate that the changes in electrode potentials which take place in Maitland cultures are not, as has been suggested, the determining factors upon which virus multiplication depends, although they may, of course, be incidentally important. It has been shown that there are fundamental differences between those conditions in Maitland cultures which favor the multiplication of a typical virus and those upon which the growth of the Rickettsiae of typhus fever depends. The virus which we have studied (equine encephalitis virus, western type) multiplies during the period of active tissue metabolism. The maximum virus titrations are obtained at about the time at which metabolism has come to a standstill. Thereafter the virus not only ceases to increase but rapidly deteriorates. The period of viability of the tissue cells themselves is shortened by several days in the presence of virus multiplication. There is some evidence that a temporary acceleration of oxygen uptake takes place during the time of active virus multiplication. Technical difficulties in controlling such experiments prevent certainty in regard to this point. In contrast with the conditions determining the growth of a virus agent in the Maitland cultures the multiplication of Rickettsiae does not begin to any determinable extent until after active cell metabolism has either become stabilized or has ceased. The Rickettsiae continue to grow at a time when the cells are no longer viable. It appears likely that these organisms find the most favorable conditions for growth in cells which are no longer metabolically active but in which some delicately heat-susceptible elements have not yet been disturbed. As a consequence of these observations, frozen and preserved embryonic tissues have been successfully used for Rickettsia cultivation. A report on these experiments will be made in a separate communication.
对梅特兰组织培养中一些生理因素的分析，希望能对阐明一般组织培养的原理有所帮助。已经发现，在这种培养中，经验上确定需要使用相对少量的组织，这取决于这样一个事实，即过多的组织会导致反应迅速向酸性侧转变。虽然组织在 pH9 以上的碱性环境中仍能存活，但当反应接近 pH6 时，其活力会迅速被破坏。有证据表明，在梅特兰培养中发生的电极电位变化，并不是像已经提出的那样，是病毒繁殖所依赖的决定因素，尽管它们当然可能偶然地很重要。已经表明，在梅特兰培养中有利于典型病毒繁殖的条件与依赖立克次体生长的条件之间存在根本差异。我们研究的病毒（马脑炎病毒，西部型）在组织代谢活跃期间繁殖。最大的病毒滴定度是在代谢停止时获得的。此后，病毒不仅停止增加，而且迅速恶化。在存在病毒繁殖的情况下，组织细胞本身的存活期缩短了几天。有一些证据表明，在活跃的病毒繁殖期间，氧摄取暂时加速。由于控制这种实验的技术困难，这一点不能确定。与决定在梅特兰培养中生长的病毒因子的条件相反，立克次体的繁殖直到活跃的细胞代谢稳定或停止后，才开始以任何可确定的程度进行。当细胞不再存活时，立克次体继续生长。这些生物体似乎在不再代谢活跃但某些对热敏感的元素尚未受到干扰的细胞中找到最有利于生长的条件。由于这些观察结果，冷冻和保存的胚胎组织已成功用于立克次体培养。关于这些实验的报告将在另一份通讯中发表。
